1. Field
This invention relates to a server client system, in particular, a thin client system, a server apparatus and a client apparatus in the thin client system, and a computer-readable medium which includes a program executed by a computer of the server apparatus and a computer of the client apparatus.
2. Description of the Related Art
In server client systems, thin client systems have attracted considerable attention as a leading measure against leakage of information. In thin client systems, client apparatuses are equipped with no HDDs but equipped with the minimum functions such as screen display and input, and all the important data are stored in the server apparatus. In addition, thin client systems have a merit that the server apparatus performs centralized management, and thereby operation management works such as upgrading and patch application of software can be reduced, which leads to reduction in the operation cost.
In such client systems, as disclosed in Jpn. Pat. Appln. KOKAI Pub. No. 2007-219626, signals from keys and pointer devices corresponding to user operations of client apparatuses are transmitted to the server apparatus each time a signal is generated, the server apparatus executes processing in accordance with the transmitted signal, generates screen data being a result of the processing, and transmits the data as drawing data to the client apparatus each time screen data is generated, and the client apparatus forms a display picture.
In thin client systems, a multi-window system is often adopted as a window system which operates in the server apparatus, like common personal computers.
When a plurality of windows are operated in the server apparatus, to operate a desired window in the client apparatus, it is necessary to operate the window after the window is rendered active, as in ordinary window systems. In addition, it is possible to use task bars and panels provided by the system. Regardless, picture transmission from the server apparatus to the client apparatus frequently occurs in the process of the operation. Therefore, in an environment in which delays occur, such as in wireless LANs and mobile phone networks, delays in processing occur when windows are switched, and the client system becomes difficult to use for the users.